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    12 May 2020, Volume 46 Issue 5
    • CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Analysis of differentially expressed genes and fiber development in Gossypium arboreum fuzzless mutant
      Xiao-Yang WANG,Li-Yuan WANG,Zhao-E PAN,Shou-Pu HE,Xiao WANG,Wen-Fang GONG,Xiong-Ming DU
      Acta Agronomica Sinica. 2020, 46(5):  645-660.  doi:10.3724/SP.J.1006.2020.94133
      Abstract ( 1177 )   HTML ( 49 )   PDF (5451KB) ( 440 )   Save
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      Cotton fiber, one of main nature textile and longest single cell, is a good material for researching the cotton fiber development. In this study, fuzz mutant (FZ) and wild-type (fz) which belong to diploid Gossypium arboreum species were used for unraveling molecular mechanism of fuzz fiber initiation by scanning electron microscopy (SEM), paraffin section and RNA sequencing technology. It was found that any fibers scarcely initiated on the ovule surface of the mutant at 0DPA, compared with that of the wild-type. Only lint fiber cells emerged on the ovule surface of fuzz mutant, while abundant fuzz and lint fiber cells appeared in wild-type at +3DPA stage. The transcriptome analysis of FZ and fz across the four fiber development stages (0DPA, +3DPA, +5DPA, and +8DPA) indicated that the number of differentially expressed gene was 3780. There were litter differentially expressed genes at 0DPA in FZ and fz. In the proceed of ovule development, the number of differentially expressed genes was increased gradually. The KEGG enriched pathway analysis illustrated that these differentially expressed genes were involved in cutin, suberine and wax biosynthesis, phenylalanine metabolism pathways and plant hormone signal transduction pathways. The analysis of co-expressed gene trend lines indicated that the up-regulated genes in mutant at +3DPA were all involved in metal ion binding, MAPK cascade, oxidoreductase activity and transcription regulation, resulting in failed fuzz fiber cells initiation in mutant. These findings elaborated a dynamic variation about fuzz fiber initiation in diploid G. arboreum, which provides a reference for further research in the cotton fiber development.

      Novel peanut genotype with low behenic acid developed from recombinant inbred lines
      Jian-Bin GUO,Li HUANG,Nian LIU,Huai-Yong LUO,Xiao-Jing ZHOU,Wei-Gang CHEN,Bei WU,Dong-Xin HUAI,Xiao-Ping REN,Hui-Fang JIANG
      Acta Agronomica Sinica. 2020, 46(5):  661-667.  doi:10.3724/SP.J.1006.2020.94119
      Abstract ( 517 )   HTML ( 20 )   PDF (391KB) ( 194 )   Save
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      Peanut is an important source of edible vegetable oil in China, and improving the quality of peanut oil is an important goal in peanut breeding. In this study, the contents of very long-chain saturated fatty acids (arachidic acid, behenic acid, and tetracosanoic acid) were determined by using RIL population containing 140 lines derived from the cross between Zhonghua 10 and ICG12625 with different genetic backgrounds. The content of very long- chain saturated fatty acid in the RILs was 4.27%-7.05%, with an average of 5.54%, the minimum value was 1.46 and 1.63 percentage points lower than that of male and female parents, with reduction rates of 25.27% and 27.62%, respectively. The behenic acid content ranged from 1.86% to 3.37%, with an average of 2.53%. Three lines of QT0002, QT0075, and QT0120 had behenic acid content lower than 2%, which was 0.57, 0.51, and 0.51 percentage points lower than that of Zhonghua10 with the reduction rate of 23.45%, 20.98%, and 20.98%, respectively. A stable QTL located in 13.31-16.34 M of B04 was detected using a linkage map and WinQTLcart software. In this region of 13.31-16.34 M contained 131 prediction genes. The results lay a foundation for the genetic improvement of low behenic acid and high-oleic peanut varieties.

      Identification of co-expressed modules of cotton genes responding to Verticillium dahliae infection by WGCNA
      Ming-Chuan FU,Hao LI,Yi-Zhen CHEN,Zhan-Ji LIU,Ren-Zhong LIU,Li-Guo WANG
      Acta Agronomica Sinica. 2020, 46(5):  668-679.  doi:10.3724/SP.J.1006.2020.94124
      Abstract ( 1313 )   HTML ( 39 )   PDF (1659KB) ( 689 )   Save
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      Weighted gene co-expression network analysis (WGCNA) is a classic systematic biological method, which can be used to identify co-expressed modules, investigate relationships between modules and specific traits, and screen hub genes in the networks. Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, can cause severe fibre quality reduction and yield loss of cotton. Studying on cotton genes and molecular mechanisms related to defense responses against V. dahliae can shed light on cotton breeding. In this study, 21 transcriptome data of Gossypium barbadense seedling roots infected by V. dahliae were used to investigate differentially expressed genes (DEGs). By filtering out the genes with low variation, 35,647 genes were selected for WGCNA. In total, 22,850 DEGs were identified under V. dahliae infection, with 4685 in common at all inoculated time points. Co-expression network analysis identified 18 modules, in which five modules significantly associated with V. dahliae infection (black, mediumpurple3, darkolivegreen, plum3 positively correlated with the 2 h, 6 h, 48 h, and 72 h inoculated time points, respectively; mediumpurple2 negatively correlated with the 2 h inoculated time point). GO and KEGG enrichment analysis were performed on these five specific modules, which could be enriched in GO terms and metabolic pathways, such as cellular response to stimulus, calcium ion binding and flavonoid biosynthesis. The hub genes were screened by calculating gene connectivity in the corresponding networks, and they may play important roles in the resistance against biotic/abiotic stresses. In summary, by WGCNA, a few defense-related co-expressed modules and hub genes were identified. The results of this study would be beneficial for further understanding of the molecular mechanisms of pathogen resistance in cotton, and provide new gene resources for cotton breeding in the future.

      Genome wide identification and expression analysis of CRK gene family in response to fungal pathogen signals in potato
      Wei-Na ZHANG,Yan-Ling FAN,Yi-Chen KANG,Xin-Yu YANG,Ming-Fu SHI,Kai YAO,Zhang-Ping ZHAO,Jun-Lian ZHANG,Shu-Hao QIN
      Acta Agronomica Sinica. 2020, 46(5):  680-689.  doi:10.3724/SP.J.1006.2020.94096
      Abstract ( 972 )   HTML ( 44 )   PDF (3639KB) ( 468 )   Save
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      Cysteine-rich receptor-like kinase (CRK) plays an important role in plant growth and environmental adaptation. In this study, potato CRK (StCRK) family members were identified, and their physical and chemical characteristics, evolutionary characteristics, subcellular location, chromosome location and expression patterns were analyzed. Eight StCRK members were identified, with amino acid size from 459 to 686 aa, molecular weight of 50.75-77.50 kD, and isoelectric point of 5.84-8.75. StCRKs were mainly located on plasma membrane. CRKs from potato (Solanum tuberosum), apple (Malus pumila Mill.), Thale Cress (Arabidopsis thaliana), rice (Oryza sativa), cotton (G. hirsutum), banana (Musa acuminata), and tomato (Solanum lycopersicum) could be divided into nine subgroups, and StCRKs were belonged to subgroups I (6 members) and VI (2 members). Moreover, StCRKs distributed on chromosomes 2, 3, and 5, contained two tandem repeat gene clusters, including four members. There were many cis-regulated elements in the StCRKs promoter region, which mainly respond to hormones, low temperature, defense and stress signals. After inoculating Phytophthora infestans (Pi) and Fusarium sulphureum (Fs), eight and six StCRKs gene differentially expressed, among them, StCRK4 and StCRK8 had the expression levels by more than eight times. It is speculated that they may respond to multiple fungal signals, and play an important role in potato's broad-spectrum resistance to fungal diseases, and can be used as candidate genes for further needed on disease resistance and functional analysis.

      Genetic analysis and molecular characterization of tasselseed mutant ts12 in maize
      Li-Ping QIN,Er-Fei DONG,Yang BAI,Lian ZHOU,Lan-Yang REN,Ren-Feng ZHANG,Chao-Xian LIU,Yi-Lin CAI
      Acta Agronomica Sinica. 2020, 46(5):  690-699.  doi:10.3724/SP.J.1006.2020.93051
      Abstract ( 1037 )   HTML ( 29 )   PDF (3390KB) ( 361 )   Save
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      Sex determination is closely associated with development of maize tassel and ear. Function study of the genes underlying maize sex determination is critical for elucidating its regulation network. One sex determination mutant with feminized tassel, named tasselseed12 (ts12), was created through B73 pollen treatment with chemical agent ethyl methyl sulfonate (EMS). The feminized tassel spikelets were observed under scanning electron microscope when the immature tassels were 13 mm long. Using map-based cloning strategy, the ts12 was mapped to an interval about 290 kb, flanked by markers LM4 and RM5, which harbored nine annotated genes including the reported sex determination gene Tasselseed2 (Ts2). The Ts2 coding sequence from ts12 mutant revealed the 196th base guanine was substituted by adenine, leading to the substitution of amino acids from glycine to arginine, which probably resulted in the tasselseed phenotype. An allelic test crossing ts2 with ts12 showed that all the F1, F2 plants could produce feminized tassels with lots of silks, which indicated ts12 was a new allelic mutant of ts2. The exogenous jasmonic acid (JA, 1 mmol L -1) could recover the normal phenotype of most of spikelets. The expression analysis of Ts12 in wild-type plants showed a high expression level in immature tassels, and moderate one in immature ears and leaves. However, its expression was dramatically decreased in immature tassels and ears of ts12. The mutation in conserved region and the reduced expression of Ts2 probably are the causes of tasselseed phenotype.

      Identification of PEPC genes from foxtail millet and its response to abiotic stress
      Jin-Feng ZHAO,Yan-Wei DU,Gao-Hong WANG,Yan-Fang LI,Gen-You ZHAO,Zhen-Hua WANG,Yu-Wen WANG,Ai-Li YU
      Acta Agronomica Sinica. 2020, 46(5):  700-711.  doi:10.3724/SP.J.1006.2020.94107
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      Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme in photosynthesis of C4 plants and plays an important role in a variety of metabolic and stress pathways. In this study, we identified six candidate PEPC genes from foxtail millet genome via sequence alignment. The characteristic parameters of all SiPEPC protein were very similar and the sequences were very conservative. All SiPEPC genes contained the PEPcase motif, which is the characteristic domain of PEPC gene. SiPEPCs were localized in cytoplasm, nucleus and mitochondrion. Promoter analysis identified a variety of light, hormonal, stress, and other growth-related cis-elements in the promoter sequences of SiPEPC members. The qRT-PCR expression profiles showed that the five SiPEPC genes (SiPEPC1, SiPEPC2, SiPEPC3, SiPEPC5, SiPEPC6) were induced by ABA, PEG, high salt and low temperature at seedling stage, indicating that five SiPEPC genes ate involved in abiotic signaling pathway at the seedling stage. The expression of five SiPEPC genes increased with the growth of foxtail millet under normal growth conditions, and increased significantly under drought stress at different growth stages, indicating that five SiPEPCs are involved in drought stress response at jointing, heading and filling stages. The weak light at jointing stage could induce the expression of five SiPEPC genes, while the expression level decreased sharply under moderate light intensity at jointing stage, moderate and weak light intensity at heading and filling stages, showing that light intensity seriously affects the expression of SiPEPC genes.

      Genetic diversity of phenotypic traits in 257 Jerusalem artichoke accessions
      Meng-Liang ZHAO,Li-Hui WANG,Yan-Jing REN,Xue-Mei SUN,Zhi-Qiang HOU,Shi-Peng YANG,Li LI,Qi-Wen ZHONG
      Acta Agronomica Sinica. 2020, 46(5):  712-724.  doi:10.3724/SP.J.1006.2020.94098
      Abstract ( 856 )   HTML ( 15 )   PDF (450KB) ( 717 )   Save
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      In order to fully understand and effectively utilize the genetic diversity of Jerusalem artichoke accessions in China. 257 Jerusalem artichoke accessions were analyzed. Among them, 12 quantitative traits had 6%-50% of the coefficient of variation, with a mean of 24.75%, which was the highest in tuber weight per plant (50%) and the smallest in growth period (6%). The diversity index (H') of these 12 traits was 1.24-1.53, with a mean of 1.44, which was the highest in tuber number per plant (1.53) and the lowest in leaf width (1.24). The diversity index of the eight quality traits was 0.85-1.08, with a mean of 0.98, which was the highest in tuber habit and the lowest in tuber uniformity, showing rich genetic diversity in most traits. The subordinate function of 257 Jerusalem artichoke accessions was 0.12-0.58, in which the highest was in JA1095 (0.58) with the obvious advantages of flower number and tuber weight per plant. The correlation analysis of 12 quantitative traits indicated that stem diameter, leaf length, flower and disk size could be used as the main target traits for high yield Jerusalem artichoke varieties breeding in the future. The results of principal component analysis showed that the cumulative contribution rate of the seven principal component factors was 66.794%. Among them, the number of flowers, the tuber number per plant, the number of tuber hairs and the smoothness of tuber epidermis were the main factors contributing to the phenotypic difference of Jerusalem artichoke. By cluster analysis, 257 accessions materials were divided into five categories based on 20 traits,among them class I and class II accounted for 85% of the total germplasm resources. This results can provide an important reference for the utilization of Jerusalem artichoke accessions and variety breeding.

      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Controlling efficiency against clubroot disease of rapeseed by mixed-cropping of susceptible and resistant cultivars
      Qing-Yun GUO, Bo WANG, Jie KUAI, Chun-Yu ZHANG, Gen-Ze LI, Hui-Xian KANG, Ting-Dong FU, Guang-Sheng ZHOU
      Acta Agronomica Sinica. 2020, 46(5):  725-733.  doi:10.3724/SP.J.1006.2020.94145
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      In recent years, rapeseed clubroot disease has spread widely in China, and the cost of the chemical control is high while the efficiency is low. Using resistant varieties is the most economical and efficient way to control this disease. Mixed-cropping different resistant varieties can improve the control efficiency of crop diseases, but the research on it has not been reported. In two naturally-infested locations of clubroot diseases in Jixi of Anhui province and Linxiang of Yunnan province, two pairs of susceptible and resistant cultivars were used (highly resistant variety Huashuang 5R mixed with highly susceptible variety Huashuang 5 and highly resistant variety Huayouza 62R mixed with highly susceptible variety Huayouza 62). Seeds of each pair were mixed at different ratios (10:0, 1:9, 2:8, 3:7, and 0:10) and sown in the two locations respectively. The incidence rate was surveyed after occurrence of clubroot disease. The mixed-cropping at different ratios of susceptible and resistant cultivars decreased the incidence and disease index of clubroot disease, and stabilized the yield and quality of rapeseed. The actual incidence rate in the mixed cropping treatment increased with the decrease of resistant cultivar proportion, which was from 5.7% to 17.1% at Jixi and from 4.4% to 32.1% at Linxiang for Huashuang 5R/Huashang 5, while from 5.7% to 18.6% at Jixi and from 2.1% to 12.0% at Linxiang for Huayouza 62R/Huayouza 62 respectively, and significantly lower than the theoretical disease incidence rate. The relative effectiveness of mixture of the two pairs of cultivars were lower than 1, which indicates that the mixed-cropping of susceptible and resistant cultivars has positive effect. This study mainly clarified the control effect of mixed-cropping two different Near-isogenic lines with different resistance levels on clubroot disease, which can provide new ideas and countermeasures for the prevention of clubroot disease.

      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Screening and identification of Chinese sorghum landraces for salt tolerance at germination and seedling stages
      Li-Ge BAO,Ping LU,Meng-Sha SHI,Yue XU,Min-Xuan LIU
      Acta Agronomica Sinica. 2020, 46(5):  734-744.  doi:10.3724/SP.J.1006.2020.94138
      Abstract ( 980 )   HTML ( 16 )   PDF (327KB) ( 856 )   Save
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      The deterioration of soil salinization has caused great harm to modern agricultural production in the world. Sorghum is not only one of five main crops, but also an outstanding salt tolerant crop. The screening and identification of sorghum salt tolerance will be very important to the development and utilization of salinized land, increasing grain yield and maintaining sustainable agricultural development. In this experiment, 110 sorghum landraces were selected to test salt tolerance at germination (200 mmol L -1 NaCl treated) and seedling stages (100 mmol L -1 NaCl treated). The two germination indicators including the germination potential and the germination rate, as well as seven seedling indicators, including the relative chlorophyll content (SPAD), seedling length, root length, seedling fresh weight, seedling dry weight, root fresh weight, root dry weight were measured. The relative values of various indicators under salt stress were calculated, showing that the relative germination potential and relative germination rate of 110 sorghum landraces were 0-98.89% and 23.65%-101.79%, and The seven seedling indicators were 59.53%-99.91%, 52.47%-95.23%, 47.87%-100.14%, 27.43%-95.28%, 30.48%-98.26%, 21.62%-100.34%, 31.46%-102.13%, respectively. Combined the membership function value analysis, principal component analysis with cluster analysis, the salt tolerance ability of the 110 landraces at germination stage and seedling stage was comprehensively evaluated and the 110 landraces were clustered into four groups. A batch of sorghum landraces with salt tolerance at germination and seedling stages were identified, especially ten landraces, including Chaoyangbangchui (00003011) from Inner Mongolia and the Baidazimao (00001081) from Beijing showed high salt tolerance, which can be used in further research. There was no significant correlation in salt tolerance between the germination stage and the seedling stage. Principal component analysis results indicated that seedling dry weight and root fresh weight can be used as indicators for the evaluation of salt tolerance of a large number of sorghum landraces at seedling stage.

      Effects of exogenous melatonin on physiology and yield of soybean during seed filling stage under drought stress
      Jing-Nan ZOU,Qi YU,Xi-Jun JIN,Ming-Yao WANG,Bin QIN,Chun-Yuan REN,Meng-Xue WANG,Yu-Xian ZHANG
      Acta Agronomica Sinica. 2020, 46(5):  745-758.  doi:10.3724/SP.J.1006.2020.94111
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      Drought stress reduces soybean yield. Exploring the mechanism of improving drought tolerance and reducing yield loss is of great significance for soybean production. Melatonin application can alleviate the growth inhibition and oxidative damage of plants under drought stress. In this experiment, the effects of foliar application of melatonin on photosynthesis, stress resistance, carbon and nitrogen metabolism and yield of soybean during seed filling stage under drought stress were studied in 2017-2018. The application exogenous melatonin increased the antioxidant enzyme activity, inhibited the production of reactive oxygen species, decreased cell membrane damage under drought stress, alleviated the inhibition of photosynthetic capacity by drought stress, improved the carbon and nitrogen assimilation ability, and alleviated the yield loss caused by drought stress. Compared with drought stress, the treatment of melatonin increased the number of pods per plant, the grain number per plant and the hundred grain weight by 2.9%, 0.8%, and 17.2% on average of two years, respectively, and the yield (grain weight per plant) increased by 14.7%.

      Effects of plough layer construction on soil three phase rate and root morphology of spring maize in northeast China
      Wei BAI,Zhan-Xiang SUN,Li-Zhen ZHANG,Jia-Ming ZHENG,Liang-Shan FENG,Qian CAI,Wu-Yan XIANG,Chen FENG,Zhe ZHANG
      Acta Agronomica Sinica. 2020, 46(5):  759-771.  doi:10.3724/SP.J.1006.2020.93044
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      Establishing reasonable plough layer construction is regarded as one of important methods for solving some rainfed farmland problems, which is of great significance in the dryland of northern China. The experiment was conducted with four tillage treatment, including furrow loose and ridge compaction plough layer (FLRC), all loose plough layer (AL), all compaction plough layer (AC), up loose and down compaction plough layer (ULDC, CK), at Fuxin National Agricultural Environmental Science Observation Experimental Station, at which the long-term plough layer construction position fixed experiment began in 2009. The data in 2015 and 2016 showed that the FLRC treatment optimized (P < 0.05) the soil three phase rate, which in 0-10 cm soil layer was optimized by AC treatment before spring corn sowing, while in 10-30 cm soil layer was optimized by FLRC and AL treatments. After the spring corn was harvested, the soil three phase’s rate in 20-30 cm soil layer in FLRC and AL treatments was better than that in ULDC and AC treatments. Compared with the ULDC treatment, FLRC treatment increased (P < 0.05) the root weight density by 7.47%-97.09%, the root length density by 6.62%-112.04%, the root surface area density by 9.80%-125.07%, and the root bulk density by 40.11%-151.97% at silking period in spring corn. The FLRC treatment significantly increased the yield of spring maize by 18.19%-34.86% (P < 0.05) due to the significant increase in number of grains and the decrease of baldness, increased the population biomass by 5.18%-11.30% (P < 0.05), and improved the harvest index (P < 0.05). In conclusion, the furrow loose and ridge compaction plough layer is the optimal construction for improving soil three phase rate and root morphology of spring maize, with certain application value in the construction of reasonable plough layer of dry farmland in northern China.

      Differences in yield and nitrogen absorption and utilization of indica-japonica hybrid rice varieties of Yongyou series
      Lei ZHOU,Qiu-Yuan LIU,Jin-Yu TIAN,Meng-Hua ZHU,Shuang CHENG,Yang CHE,Zhi-Jie WANG,Zhi-Peng XING,Ya-Jie HU,Guo-Dong LIU,Hai-Yan WEI,Hong-Cheng ZHANG
      Acta Agronomica Sinica. 2020, 46(5):  772-786.  doi:10.3724/SP.J.1006.2020.92051
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      A field experiment was conducted with 24 indica-japonica hybrid rice varieties (lines) of Yongyou series, from which three types (high yield and high AE (agronomic nitrogen use efficiency) [HH], high yield and medium AE [HM], medium yield and medium AE [MM]) were selected to explore the characteristics of varieties with high yield and high AE. The yield of HH type was 4.04%-4.38% and 13.37%-13.41% higher than that of HM type and MM type respectively, owing to the larger number of total spikelets, which was 5.87×10 8-6.20×10 8 hm -2. Compared with HM and MM type, HH type had a high percentage of tiller rate, which was 68.83%-70.05%. The LAI of HH type was maximum at heading stage and declined slowly after heading. As a result, the LAI of HH type was above 3.85 at maturity stage. The dry matter accumulation of HH type was 7.91-7.99 t hm -2from heading to maturity, which was the highest in three types, and its dry matter accumulation was more than 21.15-21.46 t hm -2 in the whole growth period. The total nitrogen uptake of HH type showed 5.07%-5.14% and 4.50%-5.96% increase than that of HM type and MM type respectively at maturity stage. The nitrogen sbsorption rate from jointing to heading stage and from heading to maturity stage showed HH type > HM type > MM type, as well as NTSH (N transportation from stem after heading), NIPH (N increase in panicle after heading) and NHI (N harvest index). HH type had the highest NRE (nitrogen recovery use efficiency), AE, PE (physiological nitrogen use efficiency) and PFP (partial factor productivity of applied N). Expect for NRE and NRG (nitrogen requirement for 100 kg grain), all the other nitrogen utilization indexes of HM type were higher than that of MM type.

      Inversion of leaf area index of winter wheat based on GF-1/2 image
      HASAN Umut,SAWUT Mamat,Shui-Sen CHEN,Dan LI
      Acta Agronomica Sinica. 2020, 46(5):  787-797.  doi:10.3724/SP.J.1006.2020.91049
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      Leaf area index (LAI) is an important parameter for monitoring crop growth, and an important input parameter for crop yield prediction model, hydrological and climatic models. LAI can be used in field crop growth monitoring and verification of remote sensing products. Therefore, accurate, rapid and large-scale estimation of LAI is not only conducive to better monitoring crops, but also conducive to its application in modeling, crop management and precision agriculture. Remote sensing technique has become a promising method to detect and monitor the crop LAI due to its many advantages. In this paper, Banjiequan Village, Wumachang Township, Qitai County, Xinjiang, China was selected as the study area. In order to rapidly and extensively retrieve LAI of winter wheat using domestic remote sensing images, 17 common vegetation indices were extracted from the GF-1/2 images, which was synchronized with field sampling, and observation at intervals of 20 m in the east-west direction and 30 m in the north-south direction in a 130 m × 420 m block. A total of 78 sampling points were taken from a small area of 4 rows × 50 cm. Sampling width was measured by tape ruler and coordinates of sampling points were given by GPS. Based on the vegetation indices extracted from GF-1/2 image and LAI data measured at erecting stage, jointing stage and flowering stage, we established univariate (linear, exponential, power, quadratic polynomials) and multivariate (partial least squares regression, PLSR) empirical models for inversion of winter wheat LAI, and validated them. The correlation coefficients of LAI with MSR (modified simple ratio), GNDVI (green normalized difference vegetation index), EVI (enhanced vegetation index) extracted from the erecting, jointing and flowering stages of GF-1 were the maximum, which were 0.708, 0.671, and 0.743, respectively, indicating that the correlation between these vegetation indices and LAI of winter wheat was significant. The univariate model R 2 based on MSRGF-1, NDVIGF-2 (normalized difference vegetation index), GNDVIGF-1 at jointing stage and EVIGF-1 at flowering stage were all greater than 0.7. Compared with different image data at the same growth stage, the quadratic polynomial model based on NDVIGF-2 and PLSR model based on NDVIGF-2, MSRGF-2, and SAVIGF-2 (soil-adjusted vegetation index) were more precise than those based on GF-1, with R 2 of 0.768 and 0.809 respectively. Compared with the models with the same data (GF-1) at different growth stages, the quadratic polynomial model based on GNDVIGF-1 at jointing stage and the PLSR model based on EVIGF-1, GSRGF-1 (green simple ratio) and NDVIGF-1 at flowering stage had the maximum value of R 2, which was 0.783. The RMSE of the PLSR model was smaller than that of the quadratic polynomial model, indicating the stability of the multivariate model was better than univariate model. Analyzing the LAI distribution maps inverted from different growth stages, it was found that the LAI inversion values basically coincided with the measured LAI values. The above results show that the domestic high-resolution remote sensing image has certain application value in crop physiological parameter inversion, and provides some references for related researches in the future.

      RESEARCH NOTES
      A dynamic model and its characteristics for nitrogen accumulation after transplanting in medium-maturity types of Yongyou japonica/indica hybrids
      Tian-Yao MENG,Jia-Lin GE,Xu-Bin ZHANG,Huan-He WEI,Yu LU,Xin-Yue LI,Yuan TAO,En-Hao DING,Gui-Sheng ZHOU,Qi-Gen DAI
      Acta Agronomica Sinica. 2020, 46(5):  798-806.  doi:10.3724/SP.J.1006.2020.92046
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      In order to quantitatively describe the dynamics of nitrogen accumulation after transplanting of medium-maturity types of Yongyou japonica/indica hybrids (MJIH), and to elucidate the mechanism of high yield based on modelling methods, MJIH Yongyou 2640 and Yongyou 1640, japonica conventional rice (JC) Yangjing 4038 and Yangjing 4227, and indica hybrid rice (IH) Xinliangyou 6380 and Yangliangyou 6 were used to compare the differences in nitrogen uptake characteristics after transplanting in 2015 and 2016. Grain yield of MJIH averaged 11.65 t hm -2 across two years, significantly higher than JC (10.74 t hm -2) and IH (10.01 t hm -2). Similar trends were also observed in nitrogen accumulation amount at maturity and nitrogen accumulation per 100 kg grain. For MJIH, the nitrogen accumulation and its ratio to total nitrogen accumulation at maturity was the highest in panicle, the medium in leaf, and lower in stem. For JC and IH, the nitrogen accumulation and its ratio to total nitrogen accumulation at maturity was the highest in panicle, the medium in stem, and lower in leaf. Compared with JC and IH, MJIH had higher ratio of leaf nitrogen accumulation, while lower ratio of panicle nitrogen accumulation to total nitrogen accumulation at maturity. There was a good fitness between Gompertz equation and dynamics of nitrogen accumulation of rice varieties in our study. Compared with JC and IH, MJIH had higher nitrogen accumulation amount in the early, middle and late nitrogen accumulation stages, which was due to long time of accumulation and higher accumulation rate in the middle stage, and higher nitrogen accumulation rate in the early and late stages. This study applied Gompertz equation to simulate the dynamics in nitrogen accumulation after transplanting of different rice varietal groups, and analyze the superiority of nitrogen accumulation of MJIH based on Gompertz equation.

Co-sponsored:
the Crop Science Society of China
the Institute of Crop Science, CAAS
China Science Publishing & Media Ltd.
Published: Science Press
Editor-in-chief: Wan Jian-min
Associate Editors-in-Chief:
Chen Xiao-ya Yang Jian-chang Zhang Xian-long Wang Jian-kang Xu Ming-liang Liu Chun-ming Wang Dao-wen Sun Chuan-qing Ding Yan-feng Jin Wei-wei Chu Cheng-cai Cheng Wei-hong
Director of the editorial department:
Yan Chun-ling
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

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  • Started in 2013
  • Covered by SCIE
  • Open access in ScienceDirect

Editor in chief: Wan Jian-min
CN 10-1112/S
ISSN 2095-5421, 2214-5141(online)
Online published:
https://www.sciencedirect.com/journal/the-crop-journal
Submission: https://www.editorialmanager.com/cj/
E-mail: cropjournal@caas.cn
Tel: 8610-82108548

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